introduction

percentile ranks

stanines

standard scores

grade equivalent scores

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A friend asks: "How are you?"

You answer: "fine, thank you."

A better answer: "compared to what?"

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Interpretation of test results is either a "compared to what" or a "compared to whom" task.

A person correctly answers 45 questions on a verbal ability test. Is this a good score?

You correctly answer 35 questions on a final exam. Did you do well?

A person reports experiencing 22 symptoms on an anxiety scale? Is this unusual?

These questions require the identification of some reference for comparison.

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The "compared to what" reference is a CRITERION-REFERENCED interpretation. In criterion-referenced interpretation the outcome of an assessment procedure is given meaning in comparison to pre-determined criteria.

Examples include:

90-100% correct will receive grade of A, 80-89% will receive B, etc.

This portfolio will be evaluated as satisfactory if it includes ten writing samples, a statement of teaching goals, etc.

The answer to the essay must include dates, countries, etc.

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In educational and psychological measurement it is often necessary to consider the typical responses of other persons in order to give meaning to the outcome of an assessment procedure.

The "compared to whom" reference is a NORM-REFERENCED interpretation.

Norm-referenced interpretation of an assessment outcome can be done by converting the raw score to:

percentile rank (sometimes a good idea)
stanines (usually a better idea)
standard scores (a more complicated alternative)
grade equivalents (not a good idea)

In any norm-referenced interpretation, IT IS CRUCIAL that you know and consider the characteristics of the group with whom the comparison is being made. _____________________________________________________________________
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For example, assume that you made a raw score of 45 on a verbal ability test..

If you are being compared with persons who have mental retardation, that score might be a percentile rank of 80 (high).

If you are being compared with a national sample of high school students, that might be a percentile rank of 50 (average).

If you are being compared with graduate students in a doctoral program, that might be a percentile rank of 20 (low).

In norm-referenced interpretation ALWAYS remember that the value of the converted score depends on the group with whom the comparison is being made.

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REVIEW QUESTION

Below is a grading scale for a college course. The syllabus says that grades in the course will be determined by total points from three examinations and assigned with the scale below :

180-200 is A
160-179 is B
140-159 is C
120-139 is D
0-119 is F

This grading scale is probably:

a. criterion-referenced
b. norm-referenced

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YOU ARE CORRECT.

The grading scale suggests criterion-referenced interpretation.

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No, this grading scale suggests criterion-referenced interpretation.

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REVIEW QUESTION

Examples of converted scores for norm-referenced interpretation include:

a. percentile ranks
b. stanines
c. standard scores
d. all of the above

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YOU ARE CORRECT.

All of the scores listed are used in norm-referenced interpretation.

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No, all of the scores listed are used in norm-referenced interpretation.

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